EVGEN/AliGenParam.cxx

   1 /**************************************************************************
   2  * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
   3  *                                                                        *
   4  * Author: The ALICE Off-line Project.                                    *
   5  * Contributors are mentioned in the code where appropriate.              *
   6  *                                                                        *
   7  * Permission to use, copy, modify and distribute this software and its   *
   8  * documentation strictly for non-commercial purposes is hereby granted   *
   9  * without fee, provided that the above copyright notice appears in all   *
  10  * copies and that both the copyright notice and this permission notice   *
  11  * appear in the supporting documentation. The authors make no claims     *
  12  * about the suitability of this software for any purpose. It is          *
  13  * provided "as is" without express or implied warranty.                  *
  14  **************************************************************************/
  15
  16 /*
  17 $Log$
  18 */
  19
  20 #include "AliGenParam.h"
  21 #include "AliGenMUONlib.h"
  22 #include "AliRun.h"
  23 #include "AliPythia.h"
  24 #include <TDirectory.h>
  25 #include <TFile.h>
  26 #include <TTree.h>
  27 #include <stdlib.h>
  28 #include <TParticle.h>
  29
  30 ClassImp(AliGenParam)
  31
  32 //------------------------------------------------------------
  33
  34   //Begin_Html
  35   /*
  36     <img src="picts/AliGenParam.gif">
  37   */
  38   //End_Html
  39
  40 //____________________________________________________________
  41 //____________________________________________________________
  42 AliGenParam::AliGenParam()
  43                  :AliGenerator()
  44 {
  45   fPtPara = 0;
  46   fYPara  = 0;
  47   fParam  = jpsi_p;
  48   fAnalog = analog;
  49   SetCutOnChild();
  50 }
  51
  52 //____________________________________________________________
  53 AliGenParam::AliGenParam(Int_t npart, Param_t param)
  54 //                                 Double_t (*PtPara)(Double_t*, Double_t*),
  55 //                                 Double_t (*YPara) (Double_t* ,Double_t*))
  56     :AliGenerator(npart)
  57 {
  58   //
  59   //  fName="HMESONpara";
  60   //  fTitle="Heavy Mesons Parametrisation";
  61   fPtParaFunc = AliGenMUONlib::GetPt(param);
  62   fYParaFunc  = AliGenMUONlib::GetY(param);
  63   fIpParaFunc = AliGenMUONlib::GetIp(param);
  64
  65   fPtPara = 0;
  66   fYPara  = 0;
  67   fParam  = param;
  68   fAnalog = analog;
  69   fChildSelect.Set(5);
  70   for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
  71   ForceDecay();
  72   SetCutOnChild();
  73 }
  74
  75 //____________________________________________________________
  76 AliGenParam::~AliGenParam()
  77 {
  78     delete  fPtPara;
  79     delete  fYPara;
  80 }
  81
  82 //____________________________________________________________
  83 void AliGenParam::Init()
  84 {
  85     SetMC(new AliPythia());
  86     fPythia= (AliPythia*) fgMCEvGen;
  87
  88 //  End of the test !!!
  89   //Begin_Html
  90   /*
  91     <img src="picts/AliGenParam.gif">
  92   */
  93   //End_Html
  94
  95   fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
  96   fYPara  = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
  97   TF1* PtPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
  98   TF1* YPara  = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
  99
 100 //
 101 // dN/dy| y=0
 102   Double_t y1=0;
 103   Double_t y2=0;
 104
 105   fdNdy0=fYParaFunc(&y1,&y2);
 106 //
 107 // Integral over generation region
 108   Float_t IntYS  = YPara ->Integral(fYMin, fYMax);
 109   Float_t IntPt0 = PtPara->Integral(0,15);
 110   Float_t IntPtS = PtPara->Integral(fPtMin,fPtMax);
 111   Float_t PhiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
 112   if (fAnalog == analog) {
 113      fYWgt  = IntYS/fdNdy0;
 114      fPtWgt = IntPtS/IntPt0;
 115      fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
 116   } else {
 117       fYWgt = IntYS/fdNdy0;
 118       fPtWgt = (fPtMax-fPtMin)/IntPt0;
 119       fParentWeight = fYWgt*fPtWgt*PhiWgt/fNpart;
 120   }
 121 //
 122 // particle decay related initialization
 123   fPythia->DefineParticles();
 124 // semimuonic decays of charm and beauty
 125   fPythia->ForceDecay(fForceDecay);
 126 //
 127     switch (fForceDecay)
 128     {
 129     case semielectronic:
 130     case dielectron:
 131     case b_jpsi_dielectron:
 132     case b_psip_dielectron:
 133         fChildSelect[0]=11;
 134         break;
 135     case semimuonic:
 136     case dimuon:
 137     case b_jpsi_dimuon:
 138     case b_psip_dimuon:
 139         fChildSelect[0]=13;
 140         break;
 141     case pitomu:
 142         fChildSelect[0]=13;
 143         break;
 144     case katomu:
 145         fChildSelect[0]=13;
 146         break;
 147     }
 148
 149 }
 150
 151 //____________________________________________________________
 152 void AliGenParam::Generate()
 153 {
 154 // Generate 'npart' of heavy mesons (J/Psi, upsilon or phi) in the
 155 // the desired theta, phi and momentum windows; Gaussian smearing
 156 // on the vertex is done if selected
 157
 158
 159   //printf("Generate !!!!!!!!!!!!!\n");
 160
 161   Float_t polar[3]= {0,0,0};
 162   //
 163   Float_t origin[3], origin0[3];
 164   Float_t pt, pl, ptot;
 165   Float_t phi, theta;
 166   Float_t p[3], pc[3], och[3], pch[10][3];
 167   Float_t ty, xmt;
 168   Int_t nt, i, j, kfch[10];
 169   Float_t  wgtp, wgtch;
 170   Double_t dummy;
 171   static TClonesArray *particles;
 172   //
 173   if(!particles) particles=new TClonesArray("TParticle",1000);
 174   //
 175   Float_t random[6];
 176   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
 177   if(fVertexSmear==perEvent) {
 178       gMC->Rndm(random,6);
 179       for (j=0;j<3;j++) {
 180           origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 181               TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 182       }
 183   }
 184   Int_t ipa=0;
 185   while (ipa<fNpart) {
 186     while(1) {
 187 //
 188 // particle type
 189           Int_t Ipart = fIpParaFunc();
 190           fChildWeight=(fPythia->GetBraPart(Ipart))*fParentWeight;
 191           Float_t am=fPythia->GetPMAS(fPythia->LuComp(Ipart),1);
 192           gMC->Rndm(random,2);
 193 //
 194 // phi
 195           phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
 196 //
 197 // y
 198           ty=Float_t(TMath::TanH(fYPara->GetRandom()));
 199 //
 200 // pT
 201           if (fAnalog == analog) {
 202               pt=fPtPara->GetRandom();
 203               wgtp=fParentWeight;
 204               wgtch=fChildWeight;
 205           } else {
 206               pt=fPtMin+random[1]*(fPtMax-fPtMin);
 207               Double_t ptd=pt;
 208               wgtp=fParentWeight*fPtParaFunc(& ptd, &dummy);
 209               wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
 210           }
 211           xmt=sqrt(pt*pt+am*am);
 212           pl=xmt*ty/sqrt(1.-ty*ty);
 213           theta=TMath::ATan2(pt,pl);
 214           if(theta<fThetaMin || theta>fThetaMax) continue;
 215           ptot=TMath::Sqrt(pt*pt+pl*pl);
 216           if(ptot<fPMin || ptot>fPMax) continue;
 217           p[0]=pt*TMath::Cos(phi);
 218           p[1]=pt*TMath::Sin(phi);
 219           p[2]=pl;
 220           if(fVertexSmear==perTrack) {
 221               gMC->Rndm(random,6);
 222               for (j=0;j<3;j++) {
 223                   origin0[j]=
 224                       fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
 225                       TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
 226               }
 227           }
 228 //
 229 // use lujet to decay particle
 230
 231           Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
 232           fPythia->DecayParticle(Ipart,energy,theta,phi);
 233           //      fPythia->LuList(1);
 234
 235
 236           //printf("origin0 %f %f %f\n",origin0[0],origin0[1],origin0[2]);
 237           //printf("fCutOnChild %d \n",fCutOnChild);
 238 //
 239 // select muons
 240           Int_t np=fPythia->ImportParticles(particles,"All");
 241           //printf("np     %d \n",np);
 242           Int_t ncsel=0;
 243           for (i = 1; i<np; i++) {
 244               TParticle *  iparticle = (TParticle *) particles->At(i);
 245               Int_t kf = iparticle->GetPdgCode();
 246               //printf("kf %d\n",kf);
 247 //
 248 // children
 249               if (ChildSelected(TMath::Abs(kf)))
 250               {
 251                   pc[0]=iparticle->Px();
 252                   pc[1]=iparticle->Py();
 253                   pc[2]=iparticle->Pz();
 254                   och[0]=origin0[0]+iparticle->Vx()/10;
 255                   och[1]=origin0[1]+iparticle->Vy()/10;
 256                   och[2]=origin0[2]+iparticle->Vz()/10;
 257                   if (fCutOnChild) {
 258                     Float_t PtChild=TMath::Sqrt(pc[0]*pc[0]+pc[1]*pc[1]);
 259                     Float_t PChild=TMath::Sqrt(PtChild*PtChild+pc[2]*pc[2]);
 260                     Float_t ThetaChild=TMath::ATan2(PtChild,pc[2]);
 261                     Float_t PhiChild=TMath::ATan2(pc[1],pc[0])+TMath::Pi();
 262                     Bool_t childok =
 263                       ((PtChild   > fPtMin   && PtChild   <fPtMax)      &&
 264                         (PChild    > fPMin    && PChild    <fPMax)       &&
 265                         (ThetaChild>fThetaMin && ThetaChild<fThetaMax)   &&
 266                         (PhiChild  >  fPhiMin && PhiChild  <fPhiMax));
 267                     if(childok)
 268                       {
 269                         pch[ncsel][0]=pc[0];
 270                         pch[ncsel][1]=pc[1];
 271                         pch[ncsel][2]=pc[2];
 272                         kfch[ncsel]=kf;
 273                         ncsel++;
 274                       } else {
 275                         ncsel=-1;
 276                         break;
 277                       } // child kine cuts
 278                   } else {
 279                     pch[ncsel][0]=pc[0];
 280                     pch[ncsel][1]=pc[1];
 281                     pch[ncsel][2]=pc[2];
 282                     kfch[ncsel]=kf;
 283                     ncsel++;
 284                   } // if child selection
 285               } // select muon
 286           } // decay particle loop
 287           Int_t iparent;
 288           if ((fCutOnChild && ncsel >0) || !fCutOnChild){
 289               ipa++;
 290 //
 291 // parent
 292               gAlice->
 293                   SetTrack(0,-1,Ipart,p,origin,polar,0,"Primary",nt,wgtp);
 294               iparent=nt;
 295
 296               for (i=0; i< ncsel; i++) {
 297                   gAlice->SetTrack(fTrackIt,iparent,kfch[i],
 298                                    &pch[i][0],och,polar,
 299                                    0,"Decay",nt,wgtch);
 300                   gAlice->KeepTrack(nt);
 301               }
 302
 303           } // kinematic selection
 304           break;
 305     } // while
 306   } // event loop
 307 }
 308
 309 Bool_t AliGenParam::ChildSelected(Int_t ip)
 310 {
 311     for (Int_t i=0; i<5; i++)
 312     {
 313         if (fChildSelect[i]==ip) return kTRUE;
 314     }
 315     return kFALSE;
 316 }
 317
 318 Bool_t AliGenParam::KinematicSelection(TParticle *particle)
 319 {
 320     Float_t px=particle->Px();
 321     Float_t py=particle->Py();
 322     Float_t pz=particle->Pz();
 323 //
 324 // momentum cut
 325     Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
 326     if (p > fPMax || p < fPMin)
 327     {
 328 //      printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
 329         return kFALSE;
 330     }
 331     Float_t pt=TMath::Sqrt(px*px+py*py);
 332
 333 //
 334 // theta cut
 335     Float_t  theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
 336     if (theta > fThetaMax || theta < fThetaMin)
 337     {
 338 //      printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
 339         return kFALSE;
 340     }
 341
 342     return kTRUE;
 343 }
 344
 345
 346
 347